The Asahi Shimbun:
” The No. 1 reactor at the Fukushima No. 1 nuclear power plant is completely exposed for the first time in five years after the last of the temporary protective covers for the crippled structure was removed Nov. 10.
The next step will be to extract nuclear fuel inside the reactor building, which was wrecked by a hydrogen explosion in the early stages of the March 2011 nuclear disaster.
The covers were installed the following October as a temporary measure against the spread of radioactive substances after the triple meltdown triggered by the Great East Japan Earthquake and tsunami.
A large crane lifted off the 20-ton cover, the last of the 18 panels installed, around 6 a.m. on Nov. 10.
Plant operator Tokyo Electric Power Co. began removing the covers one by one in September.
The 392 fuel assemblies are stored in the spent nuclear fuel pool inside the building. Melted fuel also remains inside the reactor.
TEPCO will assess the state of the reactor building’s interior in efforts to remove debris from the collapse of a roof over the spent nuclear fuel pool.
It will take precautions to prevent dust containing radioactive substances from being stirred up by shrouding the reactor building with tarpaulins. ”
by Kohei Tomida
source with aerial view video of uncovered Unit 1 reactor
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” Fukushima’s Nuclear Plant reactor No. 1 has been fully exposed for the first time since the March 2011 tragedy, after the utility company safely removed the last cover sheet of the temporary protective construction.
Tokyo Electric Power Co. (TEPCO) used an industrial crane to lift the last of its 18 protective panels Thursday. Each of the panels weighs around 20 tons and measure 23 by 17 meters.
The protective cover was erected in October 2011 as a temporary measure to halt a radiation leak following a meltdown caused by a powerful earthquake and tsunami in March 2011. The dismantling of the panels started in July 2015 and was concluded on Thursday.
At Unit 1, rubble from the damaged building caused by the hydrogen explosion remains scattered and needs to be removed. The entire site is highly contaminated and will now be covered with tarpaulins to avoid the spread of radioactive waste. TEPCO is using anti-scattering agents to keep the dust down. Small pieces of rubble that can create dust are being vacuumed up while mist sprinklers are being used inside the building to keep radiation under control.
TEPCO next plans to remove 392 fuel assemblies from the spent pool and clean out the melted nuclear fuel from inside the building, NHK news reported. The utility company is assessing the level of radiation before continuing the cleanup process.
Scientists are also installing the necessary equipment to complete fuel extraction which will only start in four years. Fuel removal from Unit 1’s depleted fuel pool is scheduled to begin around March 2021, according to TEPCO’s Mid- and Long-Term Roadmap that was revised in June 2015.
In March 2011, a tsunami destroyed emergency generators at the plant. They had been cooling the reactors. The tsunami led to three nuclear meltdowns and the release of radioactive material. In Reactor 1, overheating caused the creation of hydrogen gas. On March 12, an explosion in Unit 1 destroyed the upper part of the building.
TEPCO’s decommission plan for the Fukushima nuclear power plant implies at least a 30-40 year period before the consequences of the meltdown are fully eliminated. So far the clean-up efforts have already cost Japan in excess of $21 billion. According to the latest estimates from the Ministry of Economy, Trade and Industry, the decommissioning costs will top $105 billion. ”